In my attached Server code I send a message to the Client who receives it and returns a ACK to the server. When I send the ACK , the callback on the Server fires twice(see server.log).
I Only have one client connected and only One Subscription is present on the Client bus.
Client - http://pastebin.com/F6t9sNFz
Server - http://pastebin.com/rngJVKxk
Server.log - http://pastebin.com/ZcdU4iHa
After further evaluation, I think this issue is due to a logging issue on the server. Closing.